Composite tooling

ABSTRACT

Carbonaceous, composite tooling fabricated from pitch-based or coal-based cellular or porous products, “carbonaceous foams” having a density of preferably between about 0.1 g/cm 3  and about 0.8 g/cm 3  that are produced by: 1) conventional pitch foaming processes or; 2) the controlled heating of coal particulate preferably up to ¼ inch in diameter in a “mold” and under a non-oxidizing atmosphere. According to a specifically preferred embodiment, the starting material coal has a free swell index as determined by ASTM test D720 of between about 3.5 and about 5.0.

[0001] This application is a continuation-in-part of U.S. patentapplication Ser. No. 09/453,729 flied Dec. 12, 1999 and U.S. patentapplication Ser. No. ______ (not yet assigned) filed Jul. 10, 2001 andentitled “Cellular Coal Products and Processes”.

FIELD OF THE INVENTION

[0002] The present invention relates to tooling useful in thefabrication of structural and other members from composite materialssuch as reinforced polymer composites and the like and, moreparticularly to such tooling manufactured from carbon foams.

BACKGROUND OF THE INVENTION

[0003] The fabrication of, for example, structural members fromcomposite materials generally involves “winding” or otherwise wrappingor applying a “green” or “prepeg” form of the composite material upon amandrel or to other shaped tooling such as a mold, curing the thusapplied composite material and then removing the shape from the tooling.Many materials and technologies exist for the production of filamentwinding mandrels and composite tooling in instances where productionvolumes or quantities are large or where cost is not an issue. Morechallenging, however, are the cases of limited production of prototypeparts and the refinement of tooling designs during experimental programsor production troubleshooting. For example, the military hasdemonstrated an interest in developing tooling options for limitedquantity production, depot-level maintenance and the fabrication oftooling spare parts.

[0004] The properties of such composite tooling include: 1) tailorablethermal expansion characteristics potentially matching those of thecommonly used carbon-bismaleamide, invar, steel and aluminum toolingmaterials commonly in use; 2) compatibility with high-temperatureservice to enable adequate curing of a wide variety of resin systemsused in composite fabrication; 3) machineability to allow on-site repairand modification; and 4) relatively low cost.

[0005] The molds used in the fabrication and curing of polymer matrixcomposites have been constructed from a wide variety of materialsincluding invar, steel, aluminum, monolithic graphite, castable ceramicsand carbon-epoxy and carbon-bismaleimide systems. Mold materials mustexhibit high flexural and tensile strengths and durability, but perhapsmost importantly, they must possess a tailorable thermal expansion tomatch that of the material being formed. Vacuum integrity and low heatcapacity to allow relatively short heating and cooling times and therebyshorten fabrication cycles are also of vital importance for suchtooling. The tooling materials of the prior art were often chosen on thebasis of one or two or these desirable properties, such as strength anddurability in the case of metals, at the expense of others such astailorable thermal expansion, low heat capacity and ease ofmodification.

[0006] One attractive such metal mold material is Invar 36, a lowcarbon, 36% nickel austenitic steel that exhibits a low coefficient ofthermal expansion (CTE), excellent durability and the ability towithstand high rates of thermal cycling. Its fundamental shortcomingsare its low thermal conductivity and its weight. It is five timesheavier than carbon-epoxy tooling of the same volume, therefore oftenrequiring its application over lighter weight carbon-epoxy backingstructures.

[0007] Other approaches to solving the composite tooling issue includeelectroforming a thick nickel layer over a mandrel that is subsequentlyremoved, composite or graphite tooling over which is sprayed a metalliclayer, and plastic faced plaster (PFP. Filament winding mandrels areoften formed from metals, inflatable rubber bladders, or aluminumhoneycombs with fiber-reinforced polymer facesheets.

[0008] One of the major difficulties with the formation of large partsis the magnification of any CTE mismatch over a large area. This resultsin “spring-back” or “spring-in” as the formed composite part pulls awayfrom the tool or squeezes the tool, depending upon the direction of theCTE mismatch. An excessive CTE on the female mold can cause the part tobe crushed or trapped during cooling, while too low a CTE on the maletool can cause the part to lock onto the tool. An importantconsideration that is often ignored by mold or tooling designers is theanisotropy of composite CTE. For some polymer matrix composites, thedifference in CTE between reinforcement and matrix directions can be asgreat as 72 ppm/° C. An often proposed solution to this issue is tolower the temperature of the cure process to minimize these differences,but this is not possible with some resin systems or practical in termsof the effect on curing time.

[0009] U.S. patent application Ser. No. 09/453,729, filed Dec. 2, 1999entitled “Cellular Coal Products and Processes” and U.S. patentapplication Ser. No. ______ (not yet assigned), filed Jul. 7, 2001 andentitled “Cellular Coal Products and Processes” describe coal-basedcellular or porous products having a density of preferably between about0.1 g/cm³ and about 0.8 g/cm³ that are produced by the controlledheating of coal particulate preferably up to 1 mm in diameter in a“mold” and under a non-oxidizing atmosphere. According to specificallypreferred embodiments, the coal-based starting materials exhibit a “freeswell index” as determined by ASTM test D720 of between about 3.5 andabout 5.0. The porous products produced by these processes, preferablyas a net shape or near net shape, can be readily machined usingconventional techniques, adhered and otherwise fabricated to produce awide variety of low cost, low density products, or used in theirpreformed shape. Such cellular products have been shown to exhibitcompressive strengths of up to about 4000 psi. As described in theforegoing U.S. Patent Applications, the properties of such coal-basedcarbon foams, i.e. strength, thermal conductivity etc. can be tailoredwithin relatively broad ranges according to the requirements of aparticular application.

[0010] The application of such coal-based carbon foam materials totooling for composite materials applications would solve most, if notall of the problems with the prior art such composite tooling materialsdescribed above.

OBJECT OF THE INVENTION

[0011] It is therefore an object of the present invention to providehighly improved composite tooling that overcomes a significant number ofthe shortcomings of prior art composite tooling.

SUMMARY OF THE INVENTION

[0012] According to the present invention, there is providedcarbonaceous, composite tooling fabricated from pitch-based orcoal-based cellular or porous products, “carbonaceous foams” having adensity of preferably between about 0.1 g/cm³ and about 0.8 g/cm³ thatare produced by: 1) conventional pitch foaming processes or; 2) thecontrolled heating of coal particulate preferably up to ¼ inch indiameter in a “mold” and under a non-oxidizing atmosphere. According toa specifically preferred embodiment, the starting material coal has afree swell index as determined by ASTM test D720 of between about 3.5and about 5.0.

DESCRIPTION OF THE DRAWINGS

[0013]FIG. 1 is a graph of showing the general relationship between gasevolution and time/temperature at various operating pressures andtemperatures for the process of the present invention.

[0014]FIG. 2 is a cross-sectional view of a “mold” containing powderedcoal prior to expansion in accordance with the process of the presentinvention.

[0015]FIG. 3 is a cross-sectional view of the “mold” of FIG. 2subsequent to expansion of the powdered coal in accordance with theprocess of the present invention.

[0016]FIG. 4 is a cross-sectional diagram of an extruder suitable forthe production of coal-based porous products in accordance with thepresent invention.

[0017]FIG. 5 is a graph of linear expansion versus use temperature forseries of tailored foam tooling in accordance with the presentinvention.

DETAILED DESCRIPTION

[0018] The present invention describes tailorable composite tooling,i.e. tooling suitable for the fabrication of winding mandrels or othersuitable curing tools, fabricated from a lightweight carbon foam that isproduced by the thermal decomposition and foaming of pitch or coalderivatives under controlled conditions. The materials described hereinare especially attractive as composite tooling materials because theyoffer much lower density than conventional tooling, low, but tailorablethermal expansion coefficients and thermal conductivities and goodelevated temperature performance. Composite tooling fabricated from thematerials described herein are readily machined and repaired andproduced from very inexpensive raw materials, i.e. coal or pitch, whichare commonly available for pennies per pound.

[0019] While the foaming process described herein is not readilyportable, the composite tooling materials described herein offerfeatures that make them amenable to local level fabrication intocomposite tooling. For example, the carbon foams can be produced aslarge flat sheets, prismatic bricks, or even conformable blanks that canbe readily assembled into larger structures through the use of, forexample, graphite-phenolic adhesives or can be machined easily intovirtually any desired geometry. Conventional machining practices usingcarbide tooling and dust removal systems to capture liberated, healthhazard free graphite-like particles can be applied in the fabrication.Thus, such materials can be fabricated into large or complex structuresfrom smaller carbon foam building blocks and additionally adhered todissimilar facesheet materials, should this be desirable.

[0020] The composite tooling of the present invention comprises atooling structure, be it a mandrel, mold or other suitable formingstructure, fabricated from a pitch-based or coal-based cellular orporous product, i.e. a foam, having a density of preferably betweenabout 0.1 g/cm³ and about 0.8 g/cm³. According to a highly preferredembodiment the foam is coal-based and produced by the controlled heatingof coal particulate preferably up to {fraction (1/4)} inch in diameterin a “mold” and under a non-oxidizing atmosphere. According to aspecifically preferred embodiment, the starting material is a coalhaving a free swell index as determined by the standard ASTM D720 testof between about 3.5 and about 5.0. Such carbon based foams, withoutfurther treatment and/or the addition of strengthening additives exhibitcompressive strengths of up to about 4000 psi. Impregnation withappropriate materials or the incorporation of various strength improvingadditives can further increase the compressive, tensile and otherproperties of these cellular materials. Although a wide variety of coalsmeeting the foregoing requirements can be use to produce the carbon foammaterials described herein, they are preferably bituminous,agglomerating coals that have been comminuted to an appropriate particlesize, preferably to a fine powder below about −60 to −80 mesh.

[0021] The preferred cellular pitch or coal-based materials describedherein are semi-crystalline or more accurately turbostratically-orderedand largely isotropic i.e., demonstrating physical properties that areapproximately equal in all directions. The cellular pitch or coal-basedproducts of the present invention typically exhibit pore sizes on theorder of less than 300μ, although pore sizes of up to 500μ are possiblewithin the operating parameters of the processes described. The thermalconductivities of the cellular pitch or coal-based products aregenerally less than about 1.0 W/m/° K. Typically, the cellular pitch orcoal-based products of the present invention demonstrate compressivestrengths on the order of from about 2000 to about 6000 psi at densitiesof from about 0.4 to about 0.5 g/cm³.

[0022] It is most desirable to the successful production of compositetooling of the present invention from the coal-based foams describedherein that the coal starting material exhibit the previously specifiedfree swell index of between about 3.5 and about 5.0 and preferablybetween about 3.75 and about 4.5. Selection of starting materials withinthese parameters was determined by evaluating a large number of coalscharacterized as ranging from high to low volatiles. In general, it hasbeen found that bituminous coals exhibiting free swell indexes withinthe previously specified ranges provided the best foam products for theproduction of composite tooling in that they exhibit the lowest calcinedfoam densities and the highest calcined foam specific strengths(compressive strength/density). Coals having free swell indices belowthese preferred ranges may not agglomerate properly leaving a powdermass or sinter, but not swell or foam, while coals exhibiting free swellindices above these preferred ranges may heave upon foaming andcollapsed upon themselves leaving a dens compact. Pitch-based foams thatcan be successfully used in accordance with the present invention mustexhibit the properties described hereinabove and hereinafter for thecarbonaceous foams suitable for the fabrication of composite tooling andare in turn prepared using conventional pitch foaming techniques wellknown in the carbon arts.

[0023] The preferred coal-based foam production method of the presentinvention comprises: 1) heating a coal particulate of preferably smalli.e., less than about ¼ inch particle size in a “mold” and under anon-oxidizing atmosphere at a heat up rate of from about 1 to about 20°C. to a temperature of between about 300 and about 700° C.; 2) soakingat a temperature of between about 300 and 700° C. for from about 10minutes up to about 12 hours to form a preform or finished product; and3) controllably cooling the preform or finished product to a temperaturebelow about 100° C. The non-oxidizing atmosphere may be provided by theintroduction of inert or non-oxidizing gas into the “mold” at a pressureof from about 0 psi, i.e., free flowing gas, up to about 500 psi. Theinert gas used may be any of the commonly used inert or non-oxidizinggases such as nitrogen, helium, argon, CO₂, etc.

[0024] It is generally not desirable that the reaction chamber be ventedor leak during the heating and soaking operation. The pressure of thechamber and the increasing volatile content therein tends to retardfurther volatilization while the cellular product sinters at theindicated elevated temperatures. If the furnace is vented or leaksduring soaking, an insufficient amount of volatile matter may be presentto permit inter-particle sintering of the coal particles thus resultingin the formation of a sintered powder as opposed to the desired cellularproduct. Thus, according to a preferred embodiment of the presentprocess, venting or leakage of non-oxidizing gas and generated volatilesis inhibited consistent with the production of an acceptable cellularproduct.

[0025] Additional more convention blowing agents may be added to theparticulate prior to expansion to enhance or otherwise modify thepore-forming operation.

[0026] The term “mold”, as used herein is meant to define a mechanismfor providing controlled dimensional forming of the expanding coal.Thus, any chamber into which the coal particulate is deposited prior toor during heating and which, upon the coal powder attaining theappropriate expansion temperature, contains and shapes the expandingporous coal to some predetermined configuration such as: a flat sheet; acurved sheet; a shaped object; a building block; a rod; tube or anyother desired solid shape can be considered a “mold” for purposes of theinstant invention.

[0027] As will be apparent to the skilled artisan familiar withpressurized gas release reactions, as the pressure in the reactionvessel, in this case the mold increases, from 0 psi to 500 psi, asimposed by the non-oxidizing gas, the reaction time will increase andthe density of the produced porous coal will increase as the size of the“bubbles” or pores produced in the expanded coal decreases. Similarly, alow soak temperature at, for example about 400° C. will result in alarger pore or bubble size and consequently a less dense expanded coalthan would be achieved with a soak temperature of about 600° C. Further,the heat-up rate will also affect pore size, a faster heat-up rateresulting In a smaller pore size and consequently a denser expanded coalproduct than a slow heat-up rate. These phenomenon are, of course, dueto the kinetics of the volatile release reactions which are affected, asjust described, by the ambient pressure and temperature and the rate atwhich that temperature is achieved. These process variables can be usedto custom produce the expanded coals of the present invention in a widevariety of controlled densities, strengths etc. These results aregraphically represented in the Figure where the X axis is gas release,the Y axis is time and the individual curves represent differentpressures of inert gas P₁, P₂, and P₃, different heat-up rates HR₁, HR₂,and HR₃, and P₁<P₂<P₃ and HR₁<HR₂<HR₃.

[0028] Cooling of the composite tooling preform or composite toolingproduct after soaking is not particularly critical except as it mayresult in cracking of the composite tooling preform or product as theresult of the development of undesirable thermal stresses. Cooling ratesless than 10° C./min to a temperature of about 100° C. are typicallyused to prevent cracking due to thermal shock. Somewhat higher, butcarefully controlled, cooling rates may however, be used to obtain a“sealed skin” on the open cell structure of the product as describedbelow. The rate of cooling below 100° C. is in no way critical.

[0029] After expanding the coal particulate as just described, theporous coal product is an open celled material. Several techniques havebeen developed for “sealing” the surface of the open celled structure toimprove its adhesive capabilities, for example, for the application offacesheets of dissimilar materials for further fabrication and assemblyof a number of parts. For example, a layer of a commercially availablegraphitic adhesive can be coated onto the surface and cured at elevatedtemperature or allowed to cure at room temperature to provide anadherent skin. Alternatively, the expansion operation can be modified bycooling the expanded coal product or preform rapidly, e.g., at a rate of10° C./min or faster after expansion. It has been discovered that thisprocess modification results in the formation of a more dense skin onthe preform or product which presents a closed pore surface to theoutside of the preform or product. At these cooling rates, care must beexercised to avoid cracking of the preform or product.

[0030] After expanding, the porous coal-based preform or product isreadily machineable, sawable and otherwise readily fabricated usingconventional fabrication techniques to fabricate the composite toolingdescribed herein.

[0031] Subsequent to production of the preform or product as justdescribed, the preform or product may be subjected to carbonizationand/or graphitization according to conventional processes to obtainparticular properties desirable for specific composite toolingapplications. Additionally, a variety of additives and structuralreinforcers may be added to the coal-based preforms or products eitherbefore or after expansion to enhance specific mechanical properties suchas fracture strain, fracture toughness and impact resistance shouldthese be required for a particular composite tooling application. Forexample, particles, whiskers, fibers, plates, etc. of appropriatecarbonaceous or ceramic composition can be incorporated into the porouscoal-based composite tooling preform or product to enhance itsmechanical properties.

[0032] The open celled, coal-based composite tooling preforms orproducts of the present invention can additionally be Impregnated with,for example, petroleum pitch, epoxy resins or other polymers using avacuum assisted resin transfer type of process. The incorporation ofsuch additives provides load transfer advantages similar to thosedemonstrated in carbon composite materials. In effect a 3-D composite isproduced that demonstrates enhanced impact resistance and load transferproperties should these be required by a particular tooling application.

[0033] The cooling step in the expansion process results in somerelatively minimal shrinkage on the order of less than about 5% andgenerally in the range of from about 2% to about 3%. This shrinkage mustbe accounted for in the production of near net shape composite toolingpreforms or final products of specific dimensions and is readilydeterminable through trial and error with the particular coal startingmaterial being used. The shrinkage may be further minimized by theaddition of some inert solid material such as coke particles, ceramicparticles, ground waste from the coal expansion process etc. as iscommon practice in ceramic fabrication so long as such additions do notadversely affect the thermal conductivity or elevated temperatureperformance of the tooling.

[0034] Carbonization, sometimes referred to as calcining, isconventionally performed by heating the preform or product under anappropriate inert gas at a heat-up rate of less than about 5° C. perminute to a temperature of between about 800° C. and about 1200° C. andsoaking for from about 1 hour to about three or more hours. Appropriateinert gases are those described above that are tolerant of these hightemperatures. The inert atmosphere is supplied at a pressure of fromabout 0 psi up to a few atmospheres. The carbonization/calcinationprocess serves to remove all of the non-carbon elements present in thepreform or product such as sulfur, oxygen, hydrogen, etc that mightadversely affect the tooling in its application.

[0035] Graphitization, commonly involves heating the preform or producteither before or after carbonization at heat-up rate of less than about10° C. per minute, preferably from about 1° C. to about 5° C. perminute, to a temperature of between about 1700° C. and about 3000° C. inan atmosphere of helium or argon and soaking for a period of less thanabout one hour. Again, the inert gas may be supplied at a pressureranging from about 0 psi up to a few atmospheres.

[0036] The preferred, coal-based porous composite tooling preforms andproducts of the present invention can be produced in any solid geometricshape. Such production is possible using any number of modifiedconventional processing techniques such as extrusion, injection molding,etc. In each of such instances, the process must, of course, be modifiedto accommodate the processing characteristics of the starting materialcoal. For example, in extruding such products, as described below, thecoal powder starting material is fed by an auger into an expansionchamber where it is expanded and from which it is extruded while stillviscous. Upon exiting the extrusion die, the material is cooled toprovide a solid shape of the desired and precalculated dimensions. Toimprove the efficiency, i.e., cycle time of the process, the inputmaterial can be preheated to a temperature below the expansion point,e.g., below about 300° C., fed into the auger chamber where additionalheat is imparted to the powder with final heating being achieved justbefore extrusion through the die.

[0037] Similar relatively minor process modifications can be envisionedto fabricate the carbon foams of the present invention for use ascomposite tooling in injection molding, casting and other similarconventional material fabrication processes.

[0038] As mentioned above, the carbonaceous foam materials of thepresent invention may be coated with a wide variety of facesheetmaterials. Such facesheet coatings include, for example, but notexclusively, Kevlar® reinforced carbonaceous foam, laminated E-glassreinforced vinyl esters, Thermal spray applied coatings of a metal, forexample, aluminum or inconel etc. to achieve surface, heat transfer orthermal expansion properties compatible with specific compositematerials formed on composite tooling produced as described herein. Suchlayers can be adhered to the carbonaceous foam core using any of a widevariety of, for example, graphite-epoxy adhesives availablecommercially.

[0039] As a further enhancement of the properties of the compositetooling described herein, functionally graded foams of varying densityat their surfaces or throughout their structure may be prepared asdescribed in copending U.S. patent application Ser. No. 09/733,602,filed Dec. 8, 2000. According to this invention, coal-based cellularproducts having integral stiffeners or load paths, directed heattransfer paths and directed mass transfer paths are provided through theplacement of coal-based cells of a different size and/or density thanthose making up the matrix of the product during manufacture. There isalso provided a method for the production of coal-based cellularproducts possessing these characteristics. The method described in thisapplication utilizes the ability to select and design such propertiesthrough the proper selection and control of cell size and density. Suchcontrol of cell size and density is in turn achieved through appropriateselection of starting materials, starting material particle size, moldpacking and processing parameters. This application is incorporatedherein in its entirety.

[0040] The following examples will serve to illustrate the practice ofthe invention.

EXAMPLES Example 1

[0041] As shown in FIG. 2, a layer 10 of comminuted bituminous coalhaving a free swell index of about 4 and ground to a particle size ofabout 60 mesh and about 2 inch deep is deposited in mold 12 equippedwith a cover 16. Mold 12 is assembled from three individual piecescarbon or tool steel pieces, sides 12A and 12B and bottom 12C, alljoined together by bolts 11 and lined with a ceramic glaze or sprayapplied ceramic lining 13. Cover 16 includes a similar interior ceramiclining 15 and is attached to sides 12A and 12B with bolts 17 in thefinal assembly prior to heating. Gaskets 19 are preferably used toinsure a tight fit of cover 16 onto sides 12A and 12B. Cover 16 isoptionally equipped with a sintered vent plug 20 to permit purging ofthe interior of mold 12 with non-oxidizing gas. This configuration,incorporating valve 20 also permits pressurization, if desired tocontrol expansion speed and/or pore size in the final product asdescribed hereinabove. Nitrogen gas is repeatedly introduced throughvalve 20 to assure that all oxygen in mold 12 is purged (generally 2-4such purges have been found satisfactory) and to provide a oneatmosphere pressure of nitrogen inside of mold 12. Mold 12 is thenheated at a rate of from about 1 to about 10° C./min up to a temperatureof about between about 450 and 600° C. and held at this temperaturesufficient to devolatalize and sinter the cellular product (generallyless than about one hour). This treatment results in the production ofan open celled expanded coal product 10A as shown in FIG. 3. Mold 12 isthen cooled to room temperature at a rate of less than about 10° C./min.to a temperature of 100° C.; any remaining pressure is then ventedthrough valve 15 and the sample removed from mold 12 by disassembly ofmold 12 by disengagement of bolts 11. Expanded coal product 10A isthereby readily removed from mold 14 and is subsequently sawed to thedesired dimensions.

[0042] Product 10A has a density of between about 0.4 and about 0.6g/Cm³ and demonstrates a compressive strength on the order of betweenabout 2000 and 6000 psi. Thermal conductivity as determined by theguarded heat flow method is below about 1.0 W/m/K.

Example 2

[0043] The application of the process of the present invention in anextrusion process is depicted in FIG. 4. As shown in that figure,comminuted bituminous coal 22 of a particle size of about −80 mesh isintroduced via hopper 24 into chamber 26 equipped with auger 28 thatmoves particulate coal 18 through chamber 26 and into expansion chamber30. Chamber 26 is heated by means of a series of barrel heaters 32, 34and 36 to impart a temperature of less than about 300° C. to particulatecoal 18 as it approaches and enters expansion chamber 26. As isconventional practice in extrusion, chamber 26 is divided into a feedsection, a compression section and a metering section each definedroughly by the location of barrel heaters 32, 34 and 36 and imparted bythe tapered shape of auger 28. Expansion chamber 30 is maintained undera non-oxidizing atmosphere and at a temperature of about 450° C. bymeans of barrel heater 38. Particulate coal 18 expands within chamber 26to form expanded coal product 40 and, while still viscous, expanded coalproduct 40 is extruded through a die 42 to form solid shaped product 44upon cooling to room temperature. Solid shaped product 44 demonstratesproperties similar to those obtained from the product described inExample 1.

[0044] At the point where particulate coal 22 exits chamber 26 andenters expansion chamber 30, chamber 26 is preferably equipped with abreaker plate 46 that serves to break up any large agglomerates ofparticulate coal 22 that may have formed in transit within chamber 26.

[0045] Cellular coal-based extrudate 44 may have virtually any solidshape ranging from a large flat panel 4′×8′ as might be used as the coreof the above-described building panel to square shapes, rounds, channelsand even tubular shapes if a bridge die is used in the extrusionprocess. Almost any shape that can be achieved with plastic or metalextrusion can be similarly obtained using the process of the presentinvention.

[0046] A variety of carbonaceous foams exhibiting varying percent linearexpansions can be produced and used in accordance with the successfulpractice of the present invention, i.e. the linear expansion can betailored to meet the needs of any particular composite being fabricatedon tooling produced in accordance with the present invention. A spectrumof such materials are shown in FIG. 5 which is a graph of linearexpansion versus temperature for sample tooling produced fromcarbonaceous foams in accordance with the present invention.

[0047] As the invention has been described, it will be apparent to thoseskilled in the art that the same may be varied in many ways withoutdeparting from the spirit and scope of the invention. Any and all suchmodifications are intended to be included within the scope of theappended claims.

1-9. (Canceled)
 10. Tooling for the fabrication of composite materialscomprising a tool body comprising carbonaceous foam, wherein thecarbonaceous foam provides structural support for at least a portion ofthe composite material, and wherein the tool body is adapted forfabricating members from composite materials.
 11. The tooling of claim10, wherein said carbonaceous foam is pitch-based or coal-based.
 12. Thetooling of claim 11, wherein said carbonaceous foam is asemi-crystalline, largely isotropic, porous coal-based product producedfrom particulate coal.
 13. The tooling of claim 12, wherein said coalexhibits a free swell index of about 3.50 to about 5.0.
 14. The toolingof claim 11, wherein the carbonaceous foam has a compressive strengthbelow about 6000 psi.
 15. The tooling of claim 11, wherein saidcarbonaceous foam has been carbonized.
 16. The tooling of claim 11,wherein said carbonaceous foam has been graphitized.
 17. The tooling ofclaim 10, further comprising a facesheet of a dissimilar material coatedon the tool body.
 18. The tooling of claim 10, wherein the density ofsaid carbonaceous foam varies in density throughout the mass thereof.19. The tooling of claim 10, wherein the tool body is formed ofcarbonaceous foam that was controllably cooled to a temperature belowabout 100° C. at a rate of 10° C./min or more to provide an outersurface of the carbonaceous foam with a density higher than a density ofan outer surface of the carbonaceous foam when the carbonaceous foam iscooled at a rate of less than 10° C./min.
 20. The tooling of claim 10,wherein the coefficient of thermal expansion of the carbonaceous foam issubstantially similar to the coefficient of thermal expansion of thecomposite material.